Our research interest involves designing inhibitors for uPA, which has been implicated in mediating tumor growth and metastasis. Our approach is to couple structure-based design with random selection. To this end, we are utilizing the Computer Graphics Laboratory facility and programs such as MidasPlus to display and analyze the crystal structures of protease-inhibitor complexes, where ecotin and trypsin are used as model for our studies. Using computer graphic-assisted analysis, we were able to identify the structural motif of ecotin that is responsible fr binding to the target protease. We displayed this motif on the phage and found that it inhibits uPA in a dose-dependent fashion. Currently, we are further investigating the structure-function relationships of the mini-inhibitor.